Refrigerating apparatus



March 10, 1931.

D. E. MACCABEE REFRIGERATING APPARATUS Filed Sept. 29, 1928 Patented Mar. 10, 1931 UNITED STATES PATENT OFFICE.

DAVID E. M ACGAIBEE, OF DAYTON, OHIO, ASSIG-NOR TO FRIGIDAIRE CORPORATION, OF

. DAYTON, OHIO, A CORPORATION OF DELAWARE REFRIGERATING APPARATUS Application filed September 29, 1928. Serial No. 309,252.

This invention relates to refrigerating apparatus and particularly to soda fountains and similar devices in which various commodities of different characters" are maintained at different temperatures.

It is one of the objects of the invention to provide a simplified and economical refrigerating system particularly adapted to soda fountains;

Another object of the invention is to provide an improved and simplified arrange-- ment for maintaining a number of different temperatures by means of a single refrigerating system.

More specifically it is one of the objects of the invention to operate a plurality of refrigerating elements in series and to provide an improved and simplified means for controlling the amount of refrigeration which takes place in successive elements of the series. I

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanylng drawing, wherein a preferred form of the present invention is clearly shown. v

v The single figure of the accompanying drawing is a diagrammatic representation of a refrigerating system embodying the present invention.

It is usual to providesoda fountains with a compartment for storing ice creamwhich should be kept at a temperature of 7 F.'0I' less, a compartment for storing and cooling water on draft which should be maintained at a temperature of around and a compartment forcontainers of fountain syrups,

' fruit juices and the'like, commonly called a syrup rail, which should be maintained at a temperature of F. or less.

My invention is concerned with an improved arrangement and" method for maintaining the above mentioned compartments compartment 12 and a syrup rail 13 for holding the syrup containers. Each of the compartments may be suitably insulated according to the temperatures at which it is to be maintained. A relativel high pressure evaporator 16 is placed in t e water compartment and a relatively low pressure evaporator 17 placed in the I ice cream compartment. These evaporators are preferably of the flooded type and each includes a header 20' forming a reservoir for liquid refri erant which is kept at a constant level t erein under the control of a float valve, not shown, and refrigerant circulating tubes or coils 23. The evaporators are supplied with liquid refrigerant through liquid lines 26 and 27 connected in parallel to a condensing element generally denoted by 28 which also withdraws evaporated refrigerant from both said evaporators through a vapor conduit 29.

Refrigerant evaporated in the evaporator 16 'is withdrawn through a conduit 30 which is ultimately connected tothe conduit 29 and which isprovided with any suitable pressure regulating shut-off valve 31, the construction of which may be for example as is illustrated and described in the application of Ernest Dickey Serial No. 7 53048, filed December 1, 1924'. This valve is opened by the pressure of refrigerant in the evaporator 16 and automatically closes at some predetermined low pressure corresponding, for example, to 35 F. and thus prevents refrigeration of the evaporator below that temperature.

The'condensing element 28 includes any suitable compressor 32 actuated by a motor 33 under the control of a switch 34 which is operated in response to the pressure exist ing in the vapor conduit 29 for withdrawing gaseous (expanded) refrigerant from the conduit 29, compressing and condensing and is evaporated in and withdrawn from evaporator 16 only when the pressure regulating valve 31 is open, that is, when the temperature of 16 is above 35 F.

Liquid refrigerant is supplied from the reservoir 35 to the liquid conduits 26 and 27 by means of the conduit 40 which includes a portion or coil 41 thermally associated with the evaporator 17 and a portion 42 thermally associated with the syrup rail 13. Preferably the evaporator 17 is immersed in a non-freezing solution, such asbrine, in the ice cream compartment as is wellknown, and the coil 41 is immersed in this brine. The coil 41 and the portion 42 form heat exchangers connected in series, the first heat exchanger 41 serving to cool the liquid refrigerant to the temperature maintained by the evaporator 17, which as explained above, may be 7 F. or less, and the heat exchanger 42 serving to conduct this very cold liquid refrigerant in thermal association with the syrup rail. In passing through the syrup rail the cold liquid refrigerant absorbs heat While remaining a liquid and thus refrigerates the syrup rail. The amount of heat which is absorbed from the syrup rail is equal to MS (ri -23) Where M is the mass of liquid circulated, S the specific heat of the liquid, and t and t are the temperatures of the liquid when entering and leaving the syrup rail respectively. The temperature t is that maintained by the evaporator 17 while the temperature 25 may be any point up to 55 F., the maximum temperature at which it is desirable to maintain the syrup rail. Since in a given installation M, S and t may be regarded as constant, the amount of heat which is absorbed from the syrup rail may be regulated or adjusted by properly choosing the temperature t This may be accomplished by suitably proportioning the amount of surface of the heat exchanger 42.

The above described system provides a very simple and reliable method of cooling the syrup rail of a soda fountain and of proportioning or controlling the amount of heat which may be removed from the syrup rail to maintain the latter at a relatively high temperature by means of a refrigerating ele ment which is maintained at a relatively low temperature.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Refrigerating apparatus comprising in combination a pair of means to be cooled, an evaporator for cooling one of said means, and a conduit for supplying liquid refrigerant to the evaporator, said conduit having a portion thermally associated with the evaporator for cooling the liquid refrigerant supply and a portion between said first mentioned portlon and the evaporator for conducting the cooled refrigerant in thermal relation with the other of said means to be cooled.

2. Refrigerating apparatus comprising in combination a pair of means to be cooled, an evaporator for cooling one of said means, and a conduit for supplying liquid refrigerant to the evaporator, said conduit including a heat exchanger associated with the evaporator for cooling the liquid refrigerant supply and a second heat exchanger between said first mentioned heat exchanger and the evaporator, for cooling the other of said means.

3. Refrigerating apparatus comprisin in combination a compartment to be coole a container of liquid to be cooled, an evaporator immersed in said container and a conduit for supplying liquid refrigerant to the evaporator, said conduit including a portion immersed in said container and a portion between said immersed portion and the evaporator thermally associated with said compartment.

4;. A soda fountain comprising in combi nation an ice cream compartment, a compartment for storing syrup, and means for refrigerating said compartments including an evaporator associated with the ice cream compartment, a heat exchanger associated with the ice cream compartment, a second heat exchanger associated with the syrup compartment and connected in series between the first heat exchanger and the evaporator, and means for supplying liquid refrigerant to the first heat exchanger.

5. The method of refrigerating a pair of means to be cooled which consists in evaporating volatile refrigerant in thermal association with one of said means, conducting the liquid refrigerant to be evaporated in thermal association with said first mentioned means to cool said refrigerant and conducting said cooled refrigerant in thermal association with the other of said means to be cooled before evaporating said refrigerant.

In testimony whereof I hereto a'ffix my signature.

DAVID E. MACCABEE. 

